Selective growth of Cu nanowires on Si(111) substrates

We succeeded in the fabrication of high-aspect-ratio (length to width) Cu nanowires of less than 10 nm width and 0.5 nm height along atomic step edge lines on Si(1 1 1) substrate. The fabrication procedure consisted of two wet process steps: (1) flattening of the surface roughness to an atomic level by immersing Si(1 1 1) wafers in ultralow-dissolved-oxygen water (LOW) and (2) Cu nanowire formation by immersion in LOW containing 100 ppb Cu ions for 100 s at room temperature. The selective growth of the Cu nanowires at the step edges indicates that Cu adsorption sites could be formed there during the flattening stage.